Guidewires are used as part of the process to facilitate the advancement of vascular catheters such as angiography or angioplasty catheters through the vascular system of a patient, typically into the coronary arteries. The guidewire provides a track along which a catheter may be advanced, after the guidewire has successfully negotiated the labyrinth of blood vessels through which it may have to pass through in order to reach a desired site. The catheter thus only has to subsequently follow the track of the guidewire, which it tends to do in spontaneous manner as it is advanced.
Different guidewires are available to provide differing performance characteristics, depending upon the particular clinical need of the situation. Some guidewires are very flexible and capable of negotiating tight curves in the coronary arteries. Other guidewires are stiffer for greater pushability, with their physical characteristics being governed by their diameters, material compositions, and the like.
Particularly, the distal end of the guidewire is critical as to its physical characteristics, with the distal end often being of more flexibility than the central portion of the guidewire, the dimensions and design being proportioned to give the desired characteristics of flexibility to the distal end.
Frequently, it turns out that a guidewire which is being advanced through the arterial system of the patient is not of optimum physical characteristics to negotiate a certain internal area which the distal tip of the guidewire reaches after substantial advancement, In this circumstance, a catheter may be advanced along the guidewire. Then, the guidewire is withdrawn and replaced through the catheter with another guidewire of more desireable physical characteristics. Thus, in an angioplasty or angiographic procedure, two or more guidewires may be used in sequential order.